Staples have traditionally been used in the prior art to replace suturing when joining or anastomosing various body structures such as the bowel or bronchus. Recently, however, stapling devices have been used for ligating and dividing individual blood vessels. Traditionally, to prevent bleeding from the cut ends of the blood vessels, ligatures or vascular clips have been used. By the use of staples, however, individual rows of staple lines are used to prevent bleeding and the staple lines are generally laid perpendicularly to the blood vessel to bracket the cut ends of the blood vessel. Current linear stapler instruments apply rows of staggered staples orthogonally across the ends of the vessels thereby occluding them prior to the division or cutting of the vessel. Unfortunately, bleeding through the rows of staples is a very common problem following application of the staggered staple rows to the blood vessels. This occurs because the blood vessels are elastic and tend to stretch or contact during the application of the stapler lines and bleeding can therefore occur between the individual staples and each row of staples. To reduce such bleeding from the cut ends of blood vessels additional rows of staples have been added to the linear stapling devices of the prior art thereby increasing the number of rows of staples that perpendicularly cross the ends of the vessels. By increasing the number of rows of staples, the size of the stapling gun cartridge head and anvil must also be increased which limits the utility of the stapler instrument particularly in minimally invasive or laparoscopic surgery since access to the operative region requires the gun head to pass through trocars of very small diameter.
The increased acceptance of surgery performed by minimally invasive techniques such as laparoscopic surgery, has resulted in an increased use of linear cutter type staplers to ligate and divide blood vessels. The use of liner cutter type staplers eliminates the need for suturing or knot-tying which is difficult and tedious when performed using minimally invasive techniques. Such techniques require tiny body access incisions and the use of trocars for the insertion of instruments through the trocars in order to reach the operative region in the patient. Knot-tying techniques are time consuming and difficult to master when performing minimally invasive surgery; likewise to achieve hemostasis or to arrest blood vessel bleeding by clipping the individual vessels with metal clips pressed over the ends of the vessels prior to dividing them to achieve hemostasis is an awkward laparoscopic technique. Thus, the use of staggered staple rows orthogonally intersecting the blood vessels to achieve hemostasis is the most desirable technique in the prior art to arrest bleeding when a blood vessel is divided during minimal invasive surgery. However, because of the elasticity of the blood vessels which tend to stretch or contract during the application of the rows of staple lines, unarrested bleeding can occur between the individual staples in each row thereby precluding an effective hemostasis.